ABSTRACT
Objective @#To compare the disinfection effect of 3% (v/v) hydrogen peroxide and 500 mg/L chlorine-containing disinfectants in the independent waterway of a periodontal ultrasonic scaler to provide a reference for clinical waterway disinfection management in stomatology departments.@*Methods @#The 18 ultrasonic scalers were randomly divided into 3 groups of 6 units: the control group, experimental group 1 (3% hydrogen peroxide disinfectant group), and experimental group 2 (500 mg/L chlorine-containing disinfectant group). The replaceable parts of the independent waterway pipes of the 3 groups of ultrasonic scalers were replaced, and the water supply was supplied with sterile distilled water (DW). In the control group, special treatment was not applied to the nonreplaceable pipe part. In experimental group 1, the 3% hydrogen peroxide was used to disinfect nonreplaceable pipelines. In experimental group 2, the nonreplaceable part was disinfected with the 500 mg/L chlorine-containing disinfectant. The water sample was taken from the outlet of the scaler working part in the three groups for monitoring before disinfection, immediately after disinfection and 10 consecutive days after disinfection. Bacteria in the water samples were cultured for the colony counts. Then, the bacterial culture data were compared between groups. The qualified criterion of the water sample was that the number of bacterial colonies was less than or equal to 100 CFU/mL. After disinfection, a bacterial species mass spectrometry identification analysis was carried out when the number of bacterial colonies in each group exceeded the standard for the first time. Biofilms from the inner wall of the tube in the three groups were observed under an electron microscope on the 10th day after disinfection.@*Results @#There were no significant differences between the three groups before disinfection (F = 2.549, P = 0.111). The number of bacterial colonies in the spout of 6 scalers in the control group all exceeded the standard, and three kinds of bacteria were cultured: Sphingomonas melonis, Herbaspirillum huttiense, and Ralstonia pickettii. Compared with those in the control group, the number of bacterial colonies in experimental group 1 decreased significantly for 1-2 days after disinfection (P<0.05) and reached the standard. On the 3rd day after disinfection, the number of bacterial colonies of group 1 increased rapidly and exceeded the standard, and three kinds of bacteria were cultured: Sphingomonas, Herbaspirillum huttiense, and Ralstonia pickettii. For experimental group 2, the number of bacterial colonies decreased significantly compared to the control group on Days 1 to 6 after disinfection, but the number of bacterial colonies increased slightly from the 7th day after disinfection and exceeded the standard. Two kinds of bacteria were cultured: Herbaspirillum huttiense and Ralstonia pickettii. The average number of bacterial colonies 10-day after disinfection in experimental group 2 was lower than that in experimental group 1(P<0.001). Under an electron microscope, the biofilm thickness of the two experimental groups was significantly lower than that of the control group. @* Conclusion @# There is water pollution in the independent waterway of a periodontal ultrasound scaler. Three percent hydrogen peroxide and 500 mg/L chlorine disinfectant both have effective disinfection effects on the outlet water of scalers, and the effect of 500 mg/L chlorine disinfectant is better than that of 3% hydrogen peroxide. The use of 3% hydrogen peroxide to disinfect periodontal ultrasound scaler-independent waterways is recommended for disinfection every other day, and disinfection once a week is recommended for the use of 500 mg/L chlorine disinfectant.
ABSTRACT
Abstract@#Comprehensive sexuality education is an important part of quality education, primary and secondary schools are the most suitable places for sex education. This paper sorts out the current status of sexuality education for primary and secondary school students in developed countries after presenting the overall significance of school based sexuality education, and further points out the problems and urgency of sexuality education for primary and secondary school students in China. It also put forward the way to new directions for advocacy, including the comphrehensive sexuality education curriculum system, training of sexuality education teachers, the positive and active role of families, as well as social and community support for sexuality education in schools.